Synthetic resin and process of preparing same



Patented Mar. 14', 1939 2,150,506

UN-lTED- STATES PATENT OFFICE SYNTHETIC RESIN AND PROCESS OF PRE- PABING SAME John H. Kelly, In, Chicago, Ill.

No Drawing. Application December 23', 1935,

, Serial No. 55,933

13 Claims. (Cl. 260-104) The invention relates to synthetic resins suitt6 the action of a basic metallicoxide, changing able for incorporation into lacquer films and the the rosin of the rubber-rosin compound to a meprocess P p g e Samee partlclltallic-rosinate. This considerably neutralizes the 'larly it relates to the preparation of a fused acid value of the rosin and according to the charrubber-metallic rosinate. acter of the metallic oxide selected produces 5 In the subsequent description and claims I rosinates of different physical properties. In have used the word"rubber" in its generic sense certain fused rubber-metallic rosinate comv to include within its scope crude raw rubber, pounds, zinc, calcium and aluminum rosinates v suitably compounded unvulcanized rubber which develop very hard, firm, fused rubber-rosinate may include pigments, coloring matter, sulphur compounds resistant to moisture and water. 10 and an accelerator, waste vulcanized rubber, 're- Magnesium rosinates react similarly but proclaimed rubber, hard. rubber dust and other equivduce, when dissolved, solutions of higher viscosity, alent rubber compounds. though the solutes of all rubber-rosinates are When rubber.is fluxed and fused with rosin, verylow. While most of the basic metallic oxides the product is usually tacky and sticky and mitican be employed with more or less success, some 15 gates againstv usage in paint and lacquer comof them are not as fully suitable. Thus litharge positions. I am aware that various expedients rosinates, as also cupric rosinates, produce comhave been previously proposed to, overcome these pletely degraded, extremely sticky films, probably conditions, such as the incorporation of drying due to the depolymerization by heat and decomoils and the like, but these expedients often reposition by the oxide. All the fused rubber-mesalt in products susceptible to premature oxida tallic rosinate compounds, after dissolving in suittion. In some instances it has beenproposed to ablesolvents, give films which remain slightly predigest the rubber under pressure in alkaline tacky for several hours, but this conditiong'radusolutions, particularly when waste or hard rubber ally disappears upon atmospheric exposure. The dust has been the basic material involved, but in fused-rubber-rosinates possess excellent durabilimy process such treatment is unnecessary. ty when subjected to weathering tests and do not Again, it has been previously considered necesprematurely oxidize, fissure or'crack. sary to lower the viscosity of dissolved rubber To further improve the properties of the fused by oxidizing the solution with air currents or by rubber-rosinates, I subject them to an esterifying the useof oxidation catalysts or driers and also action with a suitable esterifying agent such as 30 by chemical reagents in order to prepare suitable glycerol. After the treatment. with a selected applications of rubber to incorporateinto cellumetallic oxide, the addition of glycerol is made- 1088 cq s slowly and steadily while agitating the mass and In my process I produce resins possessing the maintaining the temperature at 460 F. to 490 1".

viscosity in solution, durability and. excellent completed which is evidenced by the change in hardness by a different process. Accordingtomy the appearance ofmthe fumes arising from the invention, I first dissolve a small quantity of rub.-- kettle. Es'teriflcation of the rfosinate at this tember in molten rosin, adding theremaining rubperature' considerably reduces hygroscopic'charher in successive small quantities until it has been acteristics possessed by the rosinates in general. 40 completely assimilated and dissolved The tem- The resultant product, when cooled, is a hard perature ispreierably maintained tween 430 F. vitreous fused rubber-esterifled rosin mixture and 460 -F. The rubber conten .of the liquid which when dissolved in suitable solvents promixture largely predominates, and maybe as ducesfilms having brilliant lustre and extremely high as to of the total solids present durable'aging qualities. i I 45 in the mixture. The process is carried out-in At the temperatures maintained during this ordinary-kettles equipped with agitator blades reaction, esterlilcation of the rosin is probably for stirring themass and provided with a hood incompleted and asmall proportionof unchanged connected to a high speedlexhaust blower for free glycerol is probably distributed in the fused essential necessary characteristics, such as low for 30 minutes, more or less, until the reaction is carrying off. such fumes as'may arise. Heat is mixture. Such proportion of free glycerolisconpreferably gas, regulated by Bunsen type burners, sidered beneficial and exerts a marked. preservathus' enabling temperature control to be kept tion action against oxidation while the rubber within certain workable-limits. content is sufilciently high to offset the moistureter the first stage of my process is completed attractive propensities of glycerol. the hot liquid rubber rosin mix is-now su bjectecl vIn a modified process, I react the glycerol with the rubber-rosinate mixture at higher temperatures ranging between 555 F. and 560 F. This results in complete esterification of the rosinate and the reaction peak is completed within minutes. The acid number of the resin is very low, below 5 in most instances, and the resultant product, when dissolved in low boiling solvents F. to F.), can be clarified by decanting the solution or else by the usual methods available to the arts. After the solution is purified I next distill off the solvents and dry the residual resin. The resulting products are extremely hard, clear vitreous resins, possessing low solution viscosities and excellent adaptability to cellulose lacquer coatings, etc. a

What I claim as my invention is:

1. In the process of producing a fused rubberrosinate compound suitable for lacquer coatings, the step of treating a fused rubber-rosinate compound .at a temperature not substantially less than 460 F. with glycerol.

2. In the process of producing a fused rubberrosinate compound suitable for lacquer coatings, the step of treating a fused rubber-rosinate com pound with glycerol at a temperature between 430 F. and 490 F.

3. In the process of producing a fused rubberrosinate compound suitable for lacquer coatings, the step of treating a fused rubber-rosinate compound with glycerol at a temperature between 555 Rand 560 F. v

4. A resin suitable for lacquer coatings comprising an esterified fused rubber-metallic rosinate in which the rubber content predominates, said resin having low acid value and when dissolved .in solvents forms durable films resistant to premature oxidation and cracking.

5. A hard, clear vitreous resin comprising a glycerol-esterified fused rubber-metallic rosinate compound in which the rubber content predominates.

6. The process of producing a synthetic resin comprising fusing a preponderance of rubber with rosin at "a temperature not substantially less than 430 F'., reacting said fusion mixture with a basic metallic oxide forming a fused rubher-metallic rosinate, treating said rosinate with glycerol at a temperature not substantially less than 460 F..until the reaction evidenced by the change in appearance of the fumes is completed" 3 and cooling to obtain a hard, vitreous. material having low acid number and reduced hygroscopic characteristics which when dissolved in suitable solvents produces films having brilliant lustre and extremely durable aging qualities.

'7.'The process of producing a synthetic resin comprising fusinga preponderance of rubber with rosin at a temperature not substantially less than 430 F., reacting said fusion mixture with a basic metallic oxide :forming a fused rubber-metallic rosinate, treating said rosinate with glycerol at I a temperature notsubstantially less than 555 F.,

cooling to obtain a hard vitreous material, dis solving in-low boiling solvents, removing the clear solution from undissolved residue, distilling the solvents and drying the residue from said distilation.

8. The process for the manufacture of a synthetic resin suitable for incorporation into lacquer films which comprises dissolving rubber in molten rosin to obtain a mixture in which the total solids contain a predominating amount of rubber, re-' acting the hot liquid mixture with calcium oxide capable of converting the rosin in said mixture into calcium rosinate, adding glycerol, and maintainingan elevated temperature until the rosinate is esterified, thereby producing a product having hygroscopic characteristics less than rosinates in general, said product when cooled and dissolved in solvents being a lacquer capable of producing films having lustre.

9. The process for the manufacture of a synthetic resin sutable for incorporaton into lacquer films which comprises dissolving rubber in molten rosin to obtain a mixture in which the total solids contain a predominating amount of rubber, reacting the hot liquid mixture with calcium oxide capable of converting the rosin in said mixture into calcium rosinate, adding glycerol, and maintaining a temperature not substantially less than 555 F. until esterification of the rosinate is substantially complete, thereby producing a resin having a low acid number.

' 10. The process for the manufacture of asyn- 555 F. until esterification of the rosinate is substantially complete, dissolving said product, separating the clear solution from the. residue, and

evaporating the solvent, thereby obtaining a.

hard, clear, vitreous resin possessing low solution viscosity. I

11. In the process of producing a fused rubber rosinate compound suitable for lacquer coatings, the step of treating a fused rubber rosinate compound at a temperature not substantially less than 460? F. with glycerol to obtain an esterifled product.

12. In the process of producing a synthetic resin suitable for lacquer coatings, the step of treating, a fused rubber metallic rosinate compound with glycerol to obtain an esterified product.

13. A synthetic resin suitable for lacquer'coatings, comprising a glycerol-esterified fusedrubher-metallic rosinate compound in which the said compound rubber content predominates, having an acid number below 5 and being extremely hard, clear, vitreous and possessing low solution viscosity.

JOHN H. KELLY, JR. 

